This invention relates to power transmitting systems and, more particularly, to a power transmitting system which utilizes at least one endless power transmitting device such as a chain or belt with at least one variable diameter pulley whereby input-output velocity ratios may be varied in accordance with differences in pulley diameter ratios.
A primary objective of the present invention is to provide a variable ratio power transmitting system of relatively high efficiency (e.g., on the order of approximately 90 % or more) by use of essentially incompressible mechanisms which enable a substantial area of a flat surface of an essentially non-stretchable endless power transmitting device to be essentially non-slidably clamped to a substantial area of a flat surface of an essentially rigid variable diameter pulley device.
Another object is to provide clamping mechanism which is operable by relatively low operating forces under relatively low load conditions and which varies the operating force in proportion to load variations.
Another object is to enable continuous substantially infinite variation of input and output ratios within predetermined ranges.
Another object is to provide for continuous ratio changes without significant efficiency loss by changing ratios when the endless power transmitting device is disengaged from the pulley device.
Another object is to enable usage of the system under a wide range of loads without damage to the components of the system.
The foregoing and other objects and advantages of the present invention are obtained by use of clamping devices employing relatively large area surface contact rather than line or point contact between relatively movable components of the system. In addition, the inventive concepts may be employed in a manner to eliminate axial thrust loads on the pulley device.